<?php
/**
 * DES对称加密算法类
 *
 * 支持密钥：64/128/256 bit（字节长度8/16/32）
 * 支持算法：DES/AES（根据密钥长度自动匹配使用：DES:64bit AES:128/256bit）
 * 支持模式：CBC/ECB/OFB/CFB
 * 密文编码：base64字符串/十六进制字符串/二进制字符串流
 * 填充方式: PKCS5Padding（DES）
 *
 */
namespace Org\Util;

class Xcrypt
{
    /**
     * 加密算法
     *
     * @var [type]
     */
    private $mcrypt;

    /**
     * 秘钥
     *
     * @var mixed
     */
    private $key;

    /**
     * Mcrypt的加密模式
     *
     * @var string
     */
    private $mode;

    /**
     * 加密向量
     *
     * @var [type]
     */
    private $iv;

    /**
     * 加密算法的分组大小
     *
     * @var integer
     */
    private $blocksize;

    /**
     * 构造函数
     *
     * @param string 密钥
     * @param string 模式
     * @param string 向量（"off":不使用 / "auto":自动 / 其他:指定值，长度同密钥）
     *
     * @return void
     */
    public function __construct($key, $mode = 'cbc', $iv = "off")
    {
        switch (strlen($key)) {
            case 8:
                $this->mcrypt = MCRYPT_DES;
                break;
            case 16:
                $this->mcrypt = MCRYPT_RIJNDAEL_128;
                break;
            case 32:
                $this->mcrypt = MCRYPT_RIJNDAEL_256;
                break;
            default:
                die("Key size must be 8/16/32");
        }
        $this->key = $key;
        switch (strtolower($mode)) {
            case 'ofb':
                $this->mode = MCRYPT_MODE_OFB;
                if ($iv == 'off') {
                    die('OFB must give a IV');
                }
                // OFB必须有向量
                break;
            case 'cfb':
                $this->mode = MCRYPT_MODE_CFB;
                if ($iv == 'off') {
                    die('CFB must give a IV');
                }
                // CFB必须有向量
                break;
            case 'ecb':
                $this->mode = MCRYPT_MODE_ECB;
                $iv         = 'off';
                // ECB不需要向量
                break;
            case 'cbc':
            default:
                $this->mode = MCRYPT_MODE_CBC;
        }
        switch (strtolower($iv)) {
            case "off":
                $this->iv = null;
                break;
            case "auto":
                $source   = PHP_OS == 'WINNT' ? MCRYPT_RAND : MCRYPT_DEV_RANDOM;
                $this->iv = mcrypt_create_iv(mcrypt_get_block_size($this->mcrypt, $this->mode), $source);
                break;
            default:
                $this->iv = $iv;
        }
    }

    /**
     * 获取向量值
     *
     * @param string 向量值编码（base64/hex/bin）
     *
     * @return string 向量值
     */
    public function getIV($code = 'base64')
    {
        switch ($code) {
            case 'base64':
                $ret = base64_encode($this->iv);
                break;
            case 'hex':
                $ret = bin2hex($this->iv);
                break;
            case 'bin':
            default:
                $ret = $this->iv;
        }

        return $ret;
    }

    /**
     * 加密
     *
     * @param string 明文
     * @param string 密文编码（base64/hex/bin）
     *
     * @return string 密文
     */
    public function encrypt($str, $code = 'base64')
    {
        if ($this->mcrypt == MCRYPT_DES) {
            $str = $this->_pkcs5Pad($str);
        }

        if (isset($this->iv)) {
            $result = mcrypt_encrypt($this->mcrypt, $this->key, $str, $this->mode, $this->iv);
        } else {
            @$result = mcrypt_encrypt($this->mcrypt, $this->key, $str, $this->mode);
        }
        switch ($code) {
            case 'base64':
                $ret = base64_encode($result);
                break;
            case 'hex':
                $ret = bin2hex($result);
                break;
            case 'bin':
            default:
                $ret = $result;
        }

        return $ret;
    }

    /**
     * 解密
     *
     * @param string 密文
     * @param string 密文编码（base64/hex/bin）
     *
     * @return string 明文
     */
    public function decrypt($str, $code = "base64")
    {
        $ret = false;
        switch ($code) {
            case 'base64':
                $str = base64_decode($str);
                break;
            case 'hex':
                $str = $this->_hex2bin($str);
                break;
            case 'bin':
            default:
        }
        if ($str !== false) {
            if (isset($this->iv)) {
                $ret = mcrypt_decrypt($this->mcrypt, $this->key, $str, $this->mode, $this->iv);
            } else {
                @$ret = mcrypt_decrypt($this->mcrypt, $this->key, $str, $this->mode);
            }
            if ($this->mcrypt == MCRYPT_DES) {
                $ret = $this->_pkcs5Unpad($ret);
            }

            $ret = trim($ret);
        }

        return $ret;
    }

    /**
     * [_pkcs5Pad description]
     *
     * @param  [type] $text [description]
     *
     * @return [type]       [description]
     *
     * @author cliu <liuchangtao@clcw.com.cn>
     */
    private function _pkcs5Pad($text)
    {
        $this->blocksize = mcrypt_get_block_size($this->mcrypt, $this->mode);
        $pad             = $this->blocksize - (strlen($text) % $this->blocksize);
        return $text . str_repeat(chr($pad), $pad);
    }

    /**
     * [_pkcs5Unpad description]
     *
     * @param  [type] $text [description]
     *
     * @return [type]       [description]
     *
     * @author cliu <liuchangtao@clcw.com.cn>
     */
    private function _pkcs5Unpad($text)
    {
        $pad = ord($text{strlen($text) - 1});
        if ($pad > strlen($text)) {
            return false;
        }

        if (strspn($text, chr($pad), strlen($text) - $pad) != $pad) {
            return false;
        }

        $ret = substr($text, 0, -1 * $pad);
        return $ret;
    }

    /**
     * [_hex2bin description]
     *
     * @param  boolean $hex [description]
     *
     * @return [type]       [description]
     *
     * @author cliu <liuchangtao@clcw.com.cn>
     */
    private function _hex2bin($hex = false)
    {
        $ret = $hex !== false && preg_match('/^[0-9a-fA-F]+$/i', $hex) ? pack("H*", $hex) : false;
        return $ret;
    }
}
